In the summer of 1861, Henry Wadsworth Longfellow’s wife, Frances, died tragically in a fire. That first Christmas without her, he wrote in his diary, “How inexpressibly sad are the holidays.” The next year was no better, as he recorded, “ ‘A merry Christmas,’ say the children, but that is no more for me.”

In 1863, as the American Civil War was dragging on, Longfellow’s son joined the army against his father’s wishes and was critically injured. On Christmas Day that year, as church bells announced the arrival of another painful Christmas, Longfellow picked up his pen and began to write,…